Conventionally, fluid simulations owing to large-scale numerical calculations have been used in addition to wind channel tests in order to design an optimum structure in a flow field, such as an air flow or a water flow.
For example, an optimization technology of repeatedly performing fluid simulations with respect to a structure while changing the design variable of the structure by using simulated annealing, a genetic algorithm method, etc., has been developed.
Furthermore, in recent years, algorithms and programs that make it possible to mathematically deal with topologies of flow patterns by constructing a mathematical model of fluid, or the like, have been developed.
Conventional methods of optimizing structure designing, however, have a problem in that the large-scale calculations that are performed repeatedly lead to increases in calculation time and designing costs and thus, due to restrictions from them, the search area has to be limited and a possibility that the derived optimum structure is locally optimum cannot be excluded. In other words, selecting a search area has to depend on the engineer's experience and intuition and accordingly the derived result of optimization of the structure depends on which search area is set.
To deal with the problem, in Patent Document 1 “FLOW PATTERN WORD REPRESENTATION METHOD, WORD REPRESENTATION APPARATUS, AND PROGRAM (hereinafter, also referred to as “word representation theory”)”, the applicant of the present application has proposed the word representation theory in which a sequence of words is assigned to a flow that is obtained through numerical calculations and experiments and a quantitative characteristic (for example, the lift-to-drag ratio) appearing therein are represented as a qualitative sequence of subwords. Accordingly, when a structure in a flow field is designed, it is possible to easily deal with flow patterns that can be adopted to the structure without relying on experience and intuition.